"It is highly likely that the Trump administration will move to have the U.S. deploy weapons in space. If this happens, it will be profoundly destabilizing, setting off an arms race and, also likely, leading to war in space.

For decades there’s been interest by U.S. administrations—the Reagan administration with its “Star Wars” plan a leading example—in placing weapons in space. But that has alternated with some administrations more-or-less opposed, the Obama administration an example.

Still, no matter the administration, since work at the United Nations began in 1985 on a treaty seeking, as its title declares, the Prevention of an Arms Race in Outer Space, the U.S. has not supported it. Canada, Russia and China have been leaders in urging passage of this PAROS treaty, and there has been virtually universal backing from nations around the world. But by balking, U.S. administration after administration has prevented its passage."